Mr. Jacobson, 68, beat out “C,” by Tom McCarthy, widely considered the favorite to win.

The author of 10 previous novels, Mr. Jacobson, who was born in Manchester, England, was on the long list for the Booker Prize twice before, for “Who’s Sorry Now?” in 2002 and “Kalooki Nights” in 2007.

He accepted the award to unusually enthusiastic and sustained applause at an awards ceremony in London.

“I’m speechless,” he told the audience. “Fortunately, I prepared one earlier. It’s dated 1983. That’s how long the wait’s been.”

The Booker is given each year to a novel by an author in Britain, Ireland or one of the Commonwealth nations. The prize comes with a check for £50,000, or about $80,000, and a practically guaranteed jump in book sales and publicity. “The Finkler Question” was published by Bloomsbury USA this week in the United States.

It was a small triumph for humor in fiction, an argument that Mr. Jacobson made in a nearly 3,700-word essay in The Guardian last Saturday.

“There is a fear of comedy in the novel today — when did you last see the word ‘funny’ on the jacket of a serious novel? — that no one who loves the form should contemplate with pleasure,” he wrote. “We have created a false division between laughter and thought, between comedy and seriousness, between the exhilaration that the great novels offer when they are at their funniest, and whatever else it is we now think we want from literature.”

The chairman of the judging panel, Andrew Motion, Britain’s former poet laureate, called “The Finkler Question” a “marvelous book: very funny, of course, but also very clever, very sad and very subtle.”

“The Finkler Question” tells the story of Julian Treslove, an ordinary former BBC producer who meets an old philosopher friend, Sam Finkler, and their former teacher, Libor Sevcik, for dinner one night in London. Walking home, Mr. Treslove is robbed, an incident that sets him on a quest for self-discovery, wisdom and the knowledge of what it means to be Jewish.

Writing in The Guardian, Edward Docx said the novel was “full of wit, warmth, intelligence, human feeling and understanding.”

“It is also beautifully written with that sophisticated and near invisible skill of the authentic writer,” he added.

Mr. Jacobson’s selection was a reminder of the unpredictability of the Booker Prize, which is always the subject of speculation in the weeks before it is announced. Mr. McCarthy’s book was heavily favored, so much so that the online betting site Ladbrokes suspended betting last week after a huge number of wagers were placed on it — a circumstance the bookmaker called “borderline inexplicable.”

Rarely does the front-runner win the prize: last year’s award to “Wolf Hall” by Hilary Mantel was the exception, at least for recent years.

This year’s Booker short list was notable for the books that were not on it. “The Thousand Autumns of Jacob de Zoet,” by David Mitchell, and “The Slap,” by the Australian novelist Christos Tsiolkas, both made the 13-book long list but did not make the cut.

The other titles that did make the short list were: “In a Strange Room,” by Damon Galgut; “The Long Song,” by Andrea Levy; “Room,” by Emma Donoghue; and “Parrot and Olivier in America,” by Peter Carey.